Add file share server (fss)

fss.lua

@@ -0,0 +1,106 @@
+print("File Share Server")
+print("Author: Github/Kiritow")
+
+local component=require("component")
+local shell=require("shell")
+require("libevent")
+
+local args,opts=shell.parse(...)
+local argc=#args
+local function cmd(cmdstr,infostr)
+    local old=component.gpu.setForeground(0xFFFF00)
+    print(cmdstr)
+    component.gpu.setForeground(0x0000FF)
+    print(infostr)
+    component.gpu.setForeground(old)
+end
+local function err(info)
+    local old=component.gpu.setForeground(0xFF0000)
+    print(infostr)
+    component.gpu.setForeground(old)
+end
+if(argc<1) then
+    print("Usage:")
+    cmd("fss <Directory> [<Port>] [-d]",
+    "Share a directory on specific port. Default port is 21. If with -d option, fss will run background.")
+    cmd("fss -s [<Port>]",
+    "Stop background fss on specific port.")
+    return 
+end
+local op_stop=false
+local op_daemon=false
+for k in pairs(opts) do
+    if(k=="s") then
+        op_stop=true
+    elseif(k=="d") then
+        op_daemon=true
+    end
+end
+
+if(op_stop) then
+    local port=21
+    if(argc>0) then 
+        port=tonumber(args[1])
+    end
+    if(not component.modem.isOpen(port)) then
+        err("Service is not running on port " .. port)
+        return
+    end
+    local bus=CreateEventBus()
+    local done=false
+    bus:listen("fss_stopped")
+    PushEvent("fss_stop")
+    local e=bus:next()
+    bus:close()
+    print("Service stopped.")
+
+    return
+end
+
+-- Server Program
+local dir=args[1]
+local port=21
+if(argc>1) then 
+    port=tonumber(args[2])
+end
+
+local bus=CreateEventBus()
+bus:listen("modem_message")
+bus:listen("fss_stop")
+bus:listen("interrupted")
+
+local modem=component.modem
+if(not modem.open(port)) then 
+    err("Failed to start service at port "  .. port)
+    return 
+end
+
+print("File Share Server started successfully.")
+local xprint=io.write
+
+while true do 
+    local e=bus:next()
+    if(e.event=="modem_message" and e.port==port and e.data[1]=="fs_req") then
+        local filename=e.data[2]
+        local realfile=dir .. "/" .. filename
+        xprint("Requesting file: ",realfile," ")
+        local f=io.open(realfile,"rb")
+        if(f==nil) then
+            print("[Not Found]")
+            modem.send(e.senderAddress,22,"fs_ans_err")
+        else
+            local content=f:read("*a")
+            f:close()
+            modem.send(e.senderAddress,22,"fs_ans_ok",content)
+            print("[Sent]")
+        end
+    elseif(e.event=="fss_stop" or e.event=="interrupted") then
+        break
+    end
+end
+
+modem.close(port)
+bus:close()
+PushEvent("fss_stopped")
+
+print("File Share Server stopped.")